The broad objective of the present proposal is to examine changes in memory functioning in later life. The research is rooted in our earlier work which suggests that changes in memory performance may depend substantially on individual differences in the decline of information processing and intellectual ability components underlying the complex tasks typically used to measure memory. From this perspective, age- related declines in memory cannot be expected for all older adults, but only for those individuals who have experienced sufficient decline in the components necessary for successful task performance. The study is also designed to examine the potential mediators of this differential decline of processes and abilities. First, the study will examine whether such decline may be related to physical health. Second, it will investigate whether the everyday environment of many older adults may lack sufficient cognitive demand to maintain optimal memory performance. Finally, the research is designed to explore whether lower feelings of self-efficacy in memory-demanding situations may contribute to performance declines. The research is based on an ongoing longitudinal study of older adults. Participants are tested at three-year intervals, with new samples of participants added at six-year intervals. The addition of new independent samples expands the design into a sequential data collection strategy. In 1986, 484 community-dwelling adults completed a battery of tasks designed to measure memory performance, information processing and intellectual abilities, self-reported physical health, cognitive demand level of everyday activities, beliefs and feelings about cognitive functioning, and aspects of personality. In 1989, 328 of these individuals returned to be retested. The present proposal is for the third follow-up of the original sample, as well as the selection of a new sample of 500 individuals to be tested for the first time. In sum, the proposed research is designed to examine: (a) the extent to which age-related changes in memory functioning result from a pattern of differential decline of component information processing and intellectual abilities, and (b) the extent to which patterns of cognitive change in adulthood are mediated by physical health, activity life style, and personal belief variables.